Theoretical Study Of Electron Correlation Driven Superconductivity In Systems With Coexisting Wide And Narrow Bands

This book deals with the study of superconductivity in systems with coexisting wide and narrow bands. It has been previously suggested that superconductivity can be enhanced in systems with coexisting wide and narrow bands when the Fermi level is near the narrow band edge. In this book, the authors study two problems concerning this mechanism in order to: (a) provide a systematic understanding of the role of strong electron correlation effects, and (b) propose a realistic candidate material which meets the ideal criteria for high-Tc superconductivity. Regarding the role of strong correlation effects, the FLEX+DMFT method is adopted. Based on systematic calculations, the pairing mechanism is found to be indeed valid even when the strong correlation effect is considered within the formalism. In the second half of the book, the authors propose a feasible candidate material by introducing the concept of the “hidden ladder” electronic structure, arising from the combination of the bilayer lattice structure and the anisotropic orbitals of the electrons. As such, the book contributes a valuable theoretical guiding principle for seeking unknown high-Tc superconductors.

In this collection, the author has compiled a set of his papers representing some of the highlights of materials chemistry. It features a section on oxidic materials, which includes high-temperature superconductivity, colossal magnetoresistance, electronic phase separation and multiferroics. The author has also included novel methods for making gallium nitride, boron nitride and such materials, by using precursors and the urea decomposition route. Moreover, there is a section dealing with open-framework and hybrid materials of which the latter has a great future since one can make use of the rigidity of inorganic structures and the functionality and flexibility of the organic residues to design materials with novel properties.

In this collection, the author has compiled a set of his papers representing some of the highlights of materials chemistry. It features a section on oxidic materials, which includes high-temperature superconductivity, colossal magnetoresistance, electronic phase separation and multiferroics. The author has also included novel methods for making gallium nitride, boron nitride and such materials, by using precursors and the urea decomposition route. Moreover, there is a section dealing with open-framework and hybrid materials of which the latter has a great future since one can make use of the rigidity of inorganic structures and the functionality and flexibility of the organic residues to design materials with novel properties.

This primer is aimed at elevating graduate students of condensed matter theory to a level where they can engage in independent research. Topics covered include second quantisation, path and functional field integration, mean-field theory and collective phenomena.

Theory of Superconductivity is primarily intended to serve as a background for reading the literature in which detailed applications of the microscopic theory of superconductivity are made to specific problems.